Wal-Mart Stores Inc. will pay more than $33 million in back wages to thousands of employees after turning itself in to the Labor Department for paying too little in overtime over the past five years, according to an agreement announced yesterday by the U.S. Labor Department.

Wal-Mart said the department's review of its overtime calculations also found it had overpaid about 215,000 hourly workers during the same five-year period. The company said it will not seek to recover any overpayments, which were at least $20 per worker.

Separately, California's Labor Commissioner filed suit against Wal-Mart for the share of overtime shortfalls in that state. The commissioner's office said in a statement that Wal-Mart had also voluntarily notified it of the problem and was working with the commissioner.

Unlike the federal government, California has not reached a settlement, said Robert Jones, acting state labor commissioner.

He said a settlement would depend on state auditors verifying the accounting records relied upon by the Labor Department and an examination of additional records relating to more stringent California statutes, he said.

Steven Mandel, associate solicitor in the U.S. Labor Department's Fair Labor Standards Division, said the case — involving nearly 87,000 employees nationwide — resulted from Wal-Mart coming to the department in early 2005 and asking for a review of its overtime calculations.

"They had some concern that some of the practices were not in compliance" with federal wage laws, he told a conference call for reporters.

"It's not particularly unusual for an employer to come to us and talk to us about potential payroll violations," Mandel said.

But Mandel said the overtime settlement was one of the largest ever reached by the department's wage and hour division.

Wal-Mart said the settlement includes no fines or penalties and that it has adopted measures to prevent the errors from occurring again.

"The fact of the matter is we discovered this matter, we reported it to the Department of Labor and we resolved the issue," Wal-Mart spokesman John Simley said.

"We are committed to our associates (employees) and we've apologized to them for this error."

Simley said Wal-Mart discovered possible mistakes in its formulas for overtime during a regular internal review.

He said there was no connection between the company reporting itself to the Labor Department and multiple lawsuits against the retailer in recent years by employees alleging payroll violations.

Last October, Wal-Mart workers in Pennsylvania won a $78.5 million judgment for working off the clock and through rest breaks. Wal-Mart denied wrongdoing and is appealing the jury award.

One of Wal-Mart's most vociferous critics, union-backed WakeUpWalMart.com, said the overtime settlement was a sweetheart deal that favored the retailer rather than its workers.

WakeUpWalMart.com spokesman Chris Kofinis said workers were not represented in the settlement talks and added that the idea that Wal-Mart "would negotiate in the best interests of its workers is ludicrous on its face."

Critics had previously denounced a separate Labor Department settlement with Wal-Mart over child labor violations, which was made public in February 2005.

That $135,540 settlement was later found by the Labor Department's inspector general to contain significant concessions for the retailer. The inspector general's report said the settlement was "significantly different" from other such agreements and included far-reaching restrictions on the government's ability to assess monetary penalties.

The report said it found no evidence of violations of federal laws or regulations.

Regarding the overtime issue, Mandel said the department carried out a national review of all Wal-Mart stores over a two-year period from February 2005 to this year.

The settlement was approved yesterday by a federal judge in the U.S. District Court for western Arkansas, Mandel said.

The highest award to an individual employee was about $39,000, he said.